Abstract Background: Previous research has shown that substitution of high-glycaemic index (GI) bread for low-GI bread can favourably alter the 24-h glucose profile. Given the high beverage consumption in the UK, the present study aimed to evaluate the impact of consuming a beverage containing a low-GI, natural sweetener at mealtimes compared to a sucrose-based beverage, on the 24-h glucose profile. Methods: In a randomized crossover design, six subjects (aged 41 ± 16 years; body mass index = 25.8 ± 4.1 kg m−2) were provided with a diet including low-GI or control (sucrose) beverages on two nonconsecutive days. On each study day, subjects consumed the low-GI or control beverage at breakfast, lunch and dinner. Interstitial glucose concentrations were measured over 24 h using a continuous glucose monitoring system. Results: Compared to the control beverage, the low-GI beverage significantly reduced mean glucose concentration over 24 h (P P = 0.001). Conclusions: The substitution of a sucrose-based beverage for a beverage containing a low-GI, natural sweetener at mealtimes is a simple dietary change that can significantly reduce 24-h glucose levels and may be beneficial for many individuals.